Mount Prospect, Illinois 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

657
FXUS63 KLOT 251126
AFDLOT

Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
626 AM CDT Mon May 25 2026

.KEY MESSAGES...

- Above normal temperatures (highs in the 80s) are expected
  much of this week with onshore winds keeping temperatures
  cooler near the Lake Michigan shore (60s and 70s).

- Other than a low (20%) chance of showers and storms Wednesday
  afternoon near the WI/IL state line as well as near/south of
  US-24, dry conditions are favored through the end of the week.

&&

.DISCUSSION...
Issued at 330 AM CDT Mon May 25 2026

Light and variable winds and mostly clear skies paired with
increased low-level moisture from yesterday`s widespread
rainfall will set the stage for patchy fog development early
this morning. Can`t fully rule out locally dense fog into
portions of northwest Indiana but this is mostly favored just
east of the area.

Otherwise no major weather concerns are in store for today with
surface high pressure in place across the region. Mostly sunny
skies and southwesterly flow will allow temperatures to soar
into the 80s today and tomorrow for much of the area. Daily lake
breezes will keep temperatures cooler along the Lake Michigan
shore, where forecast highs are only in the low to mid 70s,
particularly on the Illinois side.

Heading into Wednesday, the local area will be situated between
two separate mid-level features of interest. The first is a
cut-off low expected to slowly lift toward the Ohio Valley
through the day. The northern periphery of the associated
showers and embedded thunderstorms has been trending farther
south with each passing day. However, the latest guidance still
suggests this could manage to lift into portions of the area,
generally near and south of US-24 (20% chance). Meanwhile, a
positively tilted mid-level wave is expected to dive southeast
out of Ontario across the Great Lakes. An associated backdoor
cold front extending across Wisconsin and Michigan will drop
southwest across the area late in the day. Showers and storms
will be possible along this front as it approaches the area,
likely decreasing in coverage with southward extent as it
encounters the locally drier airmass. There is a narrow window
where a faster frontal passage could allow isolated storms to
persist into far northern/northwest Illinois late in the
afternoon where an axis of higher instability (MLCAPE to
1000-1500 J/kg) may exist prior to sunset (20% chance).
Otherwise dry conditions are expected for the rest of the area
with temperatures in the 80s inland and 70s near the lakeshore.

A 1020+ mb Hudson Bay surface high is expected to shift south
and stall out across the western Great Lakes region midweek as
a pseudo-Omega blocking pattern becomes established across the
broader CONUS and Canada. The position of the surface high
generally favors east to northeast wind directions here locally,
potentially for several days. Accordingly, cooler conditions
are likely to continue near the Lake Michigan shore with
forecast highs only in the 60s through the upcoming weekend.
The cooler onshore flow will also extend farther inland than
earlier in the week with highs generally in the 70s to near 80.

Petr

&&

.AVIATION /12Z TAFS THROUGH 18Z TUESDAY/...
Issued at 626 AM CDT Mon May 25 2026

There is a cluster of showers moving east through northern
Iowa. However, as it approaches the Mississippi River, the front
edge of it is eroding away. There is a low (less than 15
percent) chance for some sprinkles at KRFD by late morning, but
confidence is too low to add it to the TAF. Otherwise, VFR and
dry conditions are expected through the current TAF window.

The only other impact to terminals are wind direction trends.
Southwest winds will be featured through the day before a lake
breeze is expected this afternoon, switching winds to the
southeast. Winds will then diminish this evening and become more
southerly, if not southwest.

DK

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...None.

&&

$$

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